Description

Pennsylvanian

Spotted Ridge Formation

Crook County, near Pauline, Oregon, USA.

Bark, Horsetail. Plant. Lesser-known locality.

Very fine 3-dimensional 20mm stem of a primitive horsetail.  Extremely unusual specimen from a very remote and obscure locality that is the westernmost known Pennsylvanian plant locality in the United States. Great collector piece.

Mesocalamites is an extinct genus of horsetail belonging to a group of primitive land pants (lycopsids) that formed the first forests as life invaded the tropical lowlands during the Devonian Period.   It’s found in the Mississippian of the eastern Pyrenees (French/Spanish border) and the Pennsylvanian of the United States and Bashkortostan (southern Urals).  It apparently died out by the end of the Pennsylvanian Period.  One genus of horsetails distantly related to Mesocalamites still lives today.